Speed of light homework

Q#1 : Mars and earth orbit the sun at radii of 228 million km and 150 million Km , respectively. when, in the future, your friend from Mars calls you on the phone and you answer "Hello" what are the minimum and maximum times you will have to wait for your friend to reply ?

Mars and Earth orbit on concentric roughly circular orbits around the sun. They can be either on the same side of the sun, in which case you would subtract the radiii, right? Or they could be on the opposite sides, in which case you would add them, yes? Draw a picture. But dividing distance by velocity is a good idea!